public class T {

    private static int a =1;//1代表线程1 2线程2

    public static void main(String[] args) {

        final T t = new T();

        new Thread(new Runnable() {

            @Override

            public void run() {

                synchronized (t) {

                    for(int i=1;i<=10;i++){

                        if(i==6){

                                try {

                                    a=2;//切换线程2

                                    t.wait();//线程1等待,并释放了对象的锁

                                } catch (Exception e) {

                                    e.printStackTrace();

                                }

                            }

                        System.out.println(Thread.currentThread().getName()+":"+i);

                    }

                }

            }

        }).start();;

        new Thread(new Runnable(){

            @Override

            public void run() {

                synchronized (t) {

                    if(a!=2){//没有轮到，进入等待

                        try {

                            t.wait();

                        } catch (InterruptedException e) {

                            e.printStackTrace();

                        }

                    }

                    System.out.println("hello");

                    t.notifyAll();

                }

            }

        }).start();

    }

}